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[fix] obu data corrupted after transmission

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dijunkun
2024-10-12 17:30:29 +08:00
parent 1407f67d3c
commit 6bda59b1a7
10 changed files with 170 additions and 466 deletions
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386
src/rtp/obu_parser.cpp
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@@ -14,52 +14,6 @@ constexpr int kObuTypeTemporalDelimiter = 2;
constexpr int kObuTypeTileList = 8;
constexpr int kObuTypePadding = 15;
int Leb128Size(uint64_t value) {
int size = 0;
while (value >= 0x80) {
++size;
value >>= 7;
}
return size + 1;
}
uint64_t ReadLeb128(const uint8_t*& read_at, const uint8_t* end) {
uint64_t value = 0;
int fill_bits = 0;
while (read_at != end && fill_bits < 64 - 7) {
uint8_t leb128_byte = *read_at;
value |= uint64_t{leb128_byte & 0x7Fu} << fill_bits;
++read_at;
fill_bits += 7;
if ((leb128_byte & 0x80) == 0) {
return value;
}
}
// Read 9 bytes and didn't find the terminator byte. Check if 10th byte
// is that terminator, however to fit result into uint64_t it may carry only
// single bit.
if (read_at != end && *read_at <= 1) {
value |= uint64_t{*read_at} << fill_bits;
++read_at;
return value;
}
// Failed to find terminator leb128 byte.
read_at = nullptr;
return 0;
}
int WriteLeb128(uint64_t value, uint8_t* buffer) {
int size = 0;
while (value >= 0x80) {
buffer[size] = 0x80 | (value & 0x7F);
++size;
value >>= 7;
}
buffer[size] = value;
++size;
return size;
}
const char* ObuTypeToString(OBU_TYPE type) {
switch (type) {
case OBU_SEQUENCE_HEADER:
@@ -92,25 +46,13 @@ bool ObuHasSize(uint8_t obu_header) { return obu_header & kObuSizePresentBit; }
int ObuType(uint8_t obu_header) { return (obu_header & 0b0'1111'000) >> 3; }
int MaxFragmentSize(int remaining_bytes) {
if (remaining_bytes <= 1) {
return 0;
}
for (int i = 1;; ++i) {
if (remaining_bytes < (1 << 7 * i) + i) {
return remaining_bytes - i;
}
}
}
// ParseObus
std::vector<Obu> ParseObus(uint8_t* payload, int payload_size) {
std::vector<Obu> result;
ByteBufferReader payload_reader(reinterpret_cast<const char*>(payload),
payload_size);
while (payload_reader.Length() > 0) {
Obu obu;
bool has_ext_header = false;
payload_reader.ReadUInt8(&obu.header);
obu.size = 1;
if (ObuHasExtension(obu.header)) {
@@ -123,16 +65,17 @@ std::vector<Obu> ParseObus(uint8_t* payload, int payload_size) {
}
payload_reader.ReadUInt8(&obu.extension_header);
++obu.size;
has_ext_header = true;
}
if (!ObuHasSize(obu.header)) {
obu.payload = std::vector<uint8_t>(
reinterpret_cast<const uint8_t*>(payload_reader.Data()),
payload_reader.Length());
reinterpret_cast<const uint8_t*>(payload_reader.Data()) +
payload_reader.Length());
payload_reader.Consume(payload_reader.Length());
} else {
uint64_t size = 0;
size_t len = 0;
if (!payload_reader.ReadUVarint(&size, &len) ||
if (!payload_reader.ReadUVarint(&size) ||
size > payload_reader.Length()) {
LOG_ERROR(
"Malformed AV1 input: declared payload_size {} is larger than "
@@ -140,319 +83,38 @@ std::vector<Obu> ParseObus(uint8_t* payload, int payload_size) {
size, payload_reader.Length());
return {};
}
obu.payload = std::vector<uint8_t>(
reinterpret_cast<const uint8_t*>(payload_reader.Data()), size);
reinterpret_cast<const uint8_t*>(payload_reader.Data()),
reinterpret_cast<const uint8_t*>(payload_reader.Data()) + size);
payload_reader.Consume(size);
LOG_ERROR("Has size = {}", size);
}
obu.size += obu.payload.size();
// Skip obus that shouldn't be transfered over rtp.
int obu_type = ObuType(obu.header);
// if (obu_type != kObuTypeTemporalDelimiter && obu_type != kObuTypeTileList
// &&
if (has_ext_header) {
obu.payload.insert(obu.payload.begin(), obu.extension_header);
}
obu.payload.insert(obu.payload.begin(), obu.header);
if (obu_type != kObuTypeTileList && //
obu_type != kObuTypePadding) {
result.push_back(obu);
}
// if (obu_type != kObuTypeTemporalDelimiter && //
// obu_type != kObuTypeTileList && //
// obu_type != kObuTypePadding) {
// result.push_back(obu);
// }
if (obu_type != kObuTypeTileList && obu_type != kObuTypePadding) {
result.push_back(obu);
}
}
// for (int i = 0; i < result.size(); i++) {
// LOG_ERROR("[{}] Obu size = [{}], Obu type [{}]", i,
// result[i].payload_size_,
// ObuTypeToString((OBU_TYPE)ObuType(result[i].header_)));
// }
for (int i = 0; i < result.size(); i++) {
LOG_ERROR("[{}] Obu size = [{}], Obu type [{}|{}]", i, result[i].size,
ObuType(result[i].payload[0]),
ObuTypeToString((OBU_TYPE)ObuType(result[i].header)));
}
return result;
}
int AdditionalBytesForPreviousObuElement(const Packet& packet) {
if (packet.packet_size == 0) {
// Packet is still empty => no last OBU element, no need to reserve space
// for it.
return 0;
}
if (packet.num_obu_elements > kMaxNumObusToOmitSize) {
// There is so many obu elements in the packet, all of them must be
// prepended with the length field. That imply space for the length of the
// last obu element is already reserved.
return 0;
}
// No space was reserved for length field of the last OBU element, but that
// element becoming non-last, so it now requires explicit length field.
// Calculate how many bytes are needed to store the length in leb128 format.
return Leb128Size(packet.last_obu_size);
}
std::vector<Packet> Packetize(std::vector<Obu> obus) {
int max_payload_len = 1200;
std::vector<Packet> packets;
if (obus.empty()) {
return packets;
}
// Aggregation header is present in all packets.
max_payload_len -= kAggregationHeaderSize;
// Assemble packets. Push to current packet as much as it can hold before
// considering next one. That would normally cause uneven distribution across
// packets, specifically last one would be generally smaller.
packets.emplace_back(/*first_obu_index=*/0);
int packet_remaining_bytes = max_payload_len;
for (size_t obu_index = 0; obu_index < obus.size(); ++obu_index) {
const bool is_last_obu = obu_index == obus.size() - 1;
const Obu& obu = obus[obu_index];
// Putting `obu` into the last packet would make last obu element stored in
// that packet not last. All not last OBU elements must be prepend with the
// element length. AdditionalBytesForPreviousObuElement calculates how many
// bytes are needed to store that length.
int previous_obu_extra_size =
AdditionalBytesForPreviousObuElement(packets.back());
int min_required_size =
packets.back().num_obu_elements >= kMaxNumObusToOmitSize ? 2 : 1;
if (packet_remaining_bytes < previous_obu_extra_size + min_required_size) {
// Start a new packet.
packets.emplace_back(/*first_obu_index=*/obu_index);
packet_remaining_bytes = max_payload_len;
previous_obu_extra_size = 0;
}
Packet& packet = packets.back();
// Start inserting current obu into the packet.
packet.packet_size += previous_obu_extra_size;
packet_remaining_bytes -= previous_obu_extra_size;
packet.num_obu_elements++;
bool must_write_obu_element_size =
packet.num_obu_elements > kMaxNumObusToOmitSize;
// Can fit all of the obu into the packet?
int required_bytes = obu.size;
if (must_write_obu_element_size) {
required_bytes += Leb128Size(obu.size);
}
int available_bytes = packet_remaining_bytes;
// if (is_last_obu) {
// // If this packet would be the last packet, available size is smaller.
// if (packets.size() == 1) {
// available_bytes += limits.first_packet_reduction_len;
// available_bytes -= limits.single_packet_reduction_len;
// } else {
// available_bytes -= limits.last_packet_reduction_len;
// }
// }
if (required_bytes <= available_bytes) {
// Insert the obu into the packet unfragmented.
packet.last_obu_size = obu.size;
packet.packet_size += required_bytes;
packet_remaining_bytes -= required_bytes;
continue;
}
// required_bytes larger than available_bytes, fragment the obu.
int max_first_fragment_size = must_write_obu_element_size
? MaxFragmentSize(packet_remaining_bytes)
: packet_remaining_bytes;
// Because available_bytes might be different than
// packet_remaining_bytes it might happen that max_first_fragment_size >=
// obu.size. Also, since checks above verified `obu` should not be put
// completely into the `packet`, leave at least 1 byte for later packet.
int first_fragment_size = std::min(obu.size - 1, max_first_fragment_size);
if (first_fragment_size == 0) {
// Rather than writing 0-size element at the tail of the packet,
// 'uninsert' the `obu` from the `packet`.
packet.num_obu_elements--;
packet.packet_size -= previous_obu_extra_size;
} else {
packet.packet_size += first_fragment_size;
if (must_write_obu_element_size) {
packet.packet_size += Leb128Size(first_fragment_size);
}
packet.last_obu_size = first_fragment_size;
}
// Add middle fragments that occupy all of the packet.
// These are easy because
// - one obu per packet imply no need to store the size of the obu.
// - this packets are nor the first nor the last packets of the frame, so
// packet capacity is always limits.max_payload_len.
int obu_offset;
for (obu_offset = first_fragment_size;
obu_offset + max_payload_len < obu.size;
obu_offset += max_payload_len) {
packets.emplace_back(/*first_obu_index=*/obu_index);
Packet& packet = packets.back();
packet.num_obu_elements = 1;
packet.first_obu_offset = obu_offset;
int middle_fragment_size = max_payload_len;
packet.last_obu_size = middle_fragment_size;
packet.packet_size = middle_fragment_size;
}
// Add the last fragment of the obu.
int last_fragment_size = obu.size - obu_offset;
// Check for corner case where last fragment of the last obu is too large
// to fit into last packet, but may fully fit into semi-last packet.
if (is_last_obu &&
last_fragment_size >
limits.max_payload_len - limits.last_packet_reduction_len) {
// Split last fragments into two.
if (last_fragment_size < 2) {
LOG_FATAL("last_fragment_size small than 2");
return {};
}
// Try to even packet sizes rather than payload sizes across the last
// two packets.
int semi_last_fragment_size = last_fragment_size / 2;
// But leave at least one payload byte for the last packet to avoid
// weird scenarios where size of the fragment is zero and rtp payload has
// nothing except for an aggregation header.
if (semi_last_fragment_size >= last_fragment_size) {
semi_last_fragment_size = last_fragment_size - 1;
}
last_fragment_size -= semi_last_fragment_size;
packets.emplace_back(/*first_obu_index=*/obu_index);
Packet& packet = packets.back();
packet.num_obu_elements = 1;
packet.first_obu_offset = obu_offset;
packet.last_obu_size = semi_last_fragment_size;
packet.packet_size = semi_last_fragment_size;
obu_offset += semi_last_fragment_size;
}
packets.emplace_back(/*first_obu_index=*/obu_index);
Packet& last_packet = packets.back();
last_packet.num_obu_elements = 1;
last_packet.first_obu_offset = obu_offset;
last_packet.last_obu_size = last_fragment_size;
last_packet.packet_size = last_fragment_size;
packet_remaining_bytes = max_payload_len - last_fragment_size;
}
return packets;
}
uint8_t AggregationHeader() const {
const Packet& packet = packets_[packet_index_];
uint8_t aggregation_header = 0;
// Set Z flag: first obu element is continuation of the previous OBU.
bool first_obu_element_is_fragment = packet.first_obu_offset > 0;
if (first_obu_element_is_fragment) aggregation_header |= (1 << 7);
// Set Y flag: last obu element will be continuated in the next packet.
int last_obu_offset =
packet.num_obu_elements == 1 ? packet.first_obu_offset : 0;
bool last_obu_is_fragment =
last_obu_offset + packet.last_obu_size <
obus_[packet.first_obu + packet.num_obu_elements - 1].size;
if (last_obu_is_fragment) aggregation_header |= (1 << 6);
// Set W field: number of obu elements in the packet (when not too large).
if (packet.num_obu_elements <= kMaxNumObusToOmitSize)
aggregation_header |= packet.num_obu_elements << 4;
// Set N flag: beginning of a new coded video sequence.
// Encoder may produce key frame without a sequence header, thus double check
// incoming frame includes the sequence header. Since Temporal delimiter is
// already filtered out, sequence header should be the first obu when present.
if (frame_type_ == VideoFrameType::kVideoFrameKey && packet_index_ == 0 &&
ObuType(obus_.front().header) == kObuTypeSequenceHeader) {
aggregation_header |= (1 << 3);
}
return aggregation_header;
}
bool NextPacket(RtpPacket* packet) {
if (packet_index_ >= packets_.size()) {
return false;
}
const Packet& next_packet = packets_[packet_index_];
if (next_packet.num_obu_elements < 0) {
LOG_FATAL("NextPacket: num_obu_elements < 0");
return false;
}
if (next_packet.first_obu_offset >= obus_[next_packet.first_obu].size) {
LOG_FATAL(
"next_packet.first_obu_offset >= obus_[next_packet.first_obu].size");
return false;
}
if (next_packet.last_obu_size >
obus_[next_packet.first_obu + next_packet.num_obu_elements - 1].size) {
LOG_FATAL(
"next_packet.last_obu_size>obus_[next_packet.first_obu+"
"next_packet.num_obu_elements-1].size");
return false;
}
uint8_t* const rtp_payload =
packet->AllocatePayload(kAggregationHeaderSize + next_packet.packet_size);
uint8_t* write_at = rtp_payload;
*write_at++ = AggregationHeader();
int obu_offset = next_packet.first_obu_offset;
// Store all OBU elements except the last one.
for (int i = 0; i < next_packet.num_obu_elements - 1; ++i) {
const Obu& obu = obus_[next_packet.first_obu + i];
size_t fragment_size = obu.size - obu_offset;
write_at += WriteLeb128(fragment_size, write_at);
if (obu_offset == 0) {
*write_at++ = obu.header & ~kObuSizePresentBit;
}
if (obu_offset <= 1 && ObuHasExtension(obu.header)) {
*write_at++ = obu.extension_header;
}
int payload_offset =
std::max(0, obu_offset - (ObuHasExtension(obu.header) ? 2 : 1));
size_t payload_size = obu.payload.size() - payload_offset;
if (!obu.payload.empty() && payload_size > 0) {
memcpy(write_at, obu.payload.data() + payload_offset, payload_size);
}
write_at += payload_size;
// All obus are stored from the beginning, except, may be, the first one.
obu_offset = 0;
}
// Store the last OBU element.
const Obu& last_obu =
obus_[next_packet.first_obu + next_packet.num_obu_elements - 1];
int fragment_size = next_packet.last_obu_size;
RTC_DCHECK_GT(fragment_size, 0);
if (next_packet.num_obu_elements > kMaxNumObusToOmitSize) {
write_at += WriteLeb128(fragment_size, write_at);
}
if (obu_offset == 0 && fragment_size > 0) {
*write_at++ = last_obu.header & ~kObuSizePresentBit;
--fragment_size;
}
if (obu_offset <= 1 && ObuHasExtension(last_obu.header) &&
fragment_size > 0) {
*write_at++ = last_obu.extension_header;
--fragment_size;
}
if (write_at - rtp_payload + fragment_size !=
kAggregationHeaderSize + next_packet.packet_size) {
LOG_FATAL("write_at - rtp_payload + fragment_size!=
kAggregationHeaderSize + next_packet.packet_size");
return false;
}
int payload_offset =
std::max(0, obu_offset - (ObuHasExtension(last_obu.header) ? 2 : 1));
memcpy(write_at, last_obu.payload.data() + payload_offset, fragment_size);
write_at += fragment_size;
if (write_at - rtp_payload !=
kAggregationHeaderSize + next_packet.packet_size) {
LOG_FATAL("write_at - rtp_payload!=
kAggregationHeaderSize + next_packet.packet_size");
return false;
}
++packet_index_;
bool is_last_packet_in_frame = packet_index_ == packets_.size();
packet->SetMarker(is_last_packet_in_frame && is_last_frame_in_picture_);
return true;
}
} // namespace obu